How to make off-grid solar electric cooking cheaper than wood-based cooking

Abstract

Low-income sub-Saharan Africa (SSA) households rely on wood for cooking for the simple reason that it is the lowest cost cooking fuel. Thus, full attainment of Sustainable Development Goal 7 (SDG7) requires developing clean cooking technologies that are cheaper than wood cooking. This study provides a comparative marginal levelized cost of energy (MLCOE) analysis for wood cooking vs. innovative solar electric cooking technologies. The two key off-grid solar technologies evaluated are: (1) direct-use DC solar (DDS) electricity for cooking applications, and (2) high-cycle-life lithium titanate (LTO) batteries. MLCOE is reported in USD/kWh for energy delivered to cooked food. A low median MLCOE of USD 0.125/kWh is attained using DDS electricity which is output directly by a solar panel with little or no intervening electricity storage and few electricity conversion and control costs. DDS solar panel output has variable voltage and current that is managed by a specialized DDS cooker. LTO battery-regulated electricity has a median MLCOE of USD 0.24/kWh which declines to USD 0.16/kWh with electric pressure cooker use. The distributions of MLCOE for wood-based, DDS-electric, and LTO-electric cooking strongly overlap. The MLCOE cost model suggests specific means for modifying input costs, component lifetime, and system efficiency to improve solar MLCOE further relative to wood MLCOE.